The present invention relates to an image forming apparatus for outputting a copy image by printing an image of an original on a paper sheet with use of an OA (Office Automation) apparatus such as a copying machine.
In the prior art, the direction of originals is detected for the individual originals one by one. The longitudinal direction and the transverse direction of each original are detected for automatic selection of paper sheets.
However, in the 2-in-1 printing mode in which images on both sides of an original are printed on one side of a paper sheet using an ADF (Automatic Document Feeder), the up-and-down direction of the image corresponding to the obverse side of the original may become opposite to the up-and-down direction of the image corresponding to the reverse side of the original, depending on the direction in which the original is set on the original table.
For example, in the case of printing of both sides of an original with the setting of “A4, portrait, horizontal description” and “binding in longitudinal direction”, when an original is set in the direction of A4, images corresponding to the images on both sides of the original are arranged on the right and left parts of a paper sheet in the same up-and-down direction. However, when an original is set in the direction of A4-R (Reduction), the up-and-down direction of the image corresponding to the obverse side of the original is opposite to the up-and-down direction of the image corresponding to the reverse side of the original.
On the other hand, in the case of printing of both sides of an original with the setting of “A4, landscape, horizontal description” and “binding in transverse direction”, when an original is set in the direction of A4-R, images corresponding to the images on both sides of the original are arranged on the right and left parts of a paper sheet in the same up-and-down direction. However, when an original is set in the direction of A4, the up-and-down direction of the image corresponding to the obverse side of the original is opposite to the up-and-down direction of the image corresponding to the reverse side of the original.
Whether the image on the obverse side of an original and the image on the reverse side of the original are arranged on the left and right parts of a paper sheet or on the right and left parts of the paper sheet varies depending on whether the images on the original are horizontal description or vertical description. Since this setting by the user is time-consuming, there is a proposal that characters extracted from the original are recognized to determine the up-and-down direction of the original and to automatically set the up-and-down direction of the original.
The portrait of the horizontally positioned original is defined such that the longitudinal direction of the original coincides with the up-and-down direction of the image. The landscape of the horizontally positioned original is defined such that the transverse direction of the original coincides with the up-and-down direction of the image.
The setting of an original in the direction of A4 is defined such that the convey direction of an A4-sized document is perpendicular to the longitudinal direction of the original, and the main scan direction of the original by the scanner coincides with the longitudinal direction of the original.
The setting of an original in the direction of A4-R is defined such that the convey direction of an A4-sized document is perpendicular to the transverse direction of the original, and the main scan direction of the original by the scanner coincides with the transverse direction of the original.
Accordingly, character recognition is indispensable for both-side copying of an original without a user's time-consuming procedure. Although there are some patents relating to the method of determining the up-and-down direction of originals using character recognition, these are based on the technique wherein character recognition is made at the time of inputting all originals. Since a considerable length of time is needed for character recognition, there is a problem that the copying performance will greatly deteriorate due to the character recognition of all originals.
In order to solve this problem, there is a proposal which pays attention to the fact that in most cases the up-and-down directions of originals to be used by the user are identical. In this proposal, character recognition for only the first of the originals is effected. Based on the character recognition of the first original, a rotational process and an arrangement process at the time of input of originals are determined. No character recognition is performed for the second and following originals, and these originals are uniformly subjected to the processes determined in connection with the first original. Thereby, the deterioration in copying performance is reduced.
However, since the character recognition is performed at the time of inputting the first original, the start of the input process for the next original will disadvantageously delay, and deterioration in scan performance will be caused.
For example, as shown in FIG. 1, after a first original has been scanned, a process of detecting the direction of the first original is performed. Consequently, an unnecessary time interval of 1 to 2 seconds exists between the scan of the first original and the scan of the second original.